Insulating glass elements can consist of two or more glass panes and a spacer which is respectively introduced between the two mutually facing glass surfaces of two respective opposite glass panes and which forms a closed frame. Twin-pane insulating glass elements therefore comprise an edge joint which extends around the circumference of the insulating glass element, and multi-pane insulating glass elements may comprise more than one such edge joint. The edge joints of a multi-pane insulating glass element can be filled successively with a sealing compound, but they can also be sealed simultaneously (in parallel or in a staggered manner).
The glass panes which form the respective insulating glass element can be congruent or incongruent. Insulating glass elements with incongruent glass panes are known as step elements. The panes that form the insulating glass element can have rectangular shape or any arbitrary (“contoured”) form. Round-arch and gable-arch shapes are usual forms of insulating glass elements which deviate from the rectangular form.
The sealing of insulating glass elements occurs in such a way that the edge joint, which remains free on the exterior circumference of the insulating glass element, is preferably fully filled with a sealing compound once the glass panes have been joined under intermediate joining of the spacer frame. The compound solidifies after the introduction.
Hot processed thermoplastic material on the basis of polyisobutylene or setting reactive material on the basis of silicone, polysulphide or polyurethane can be used as a sealing compound. It is the object of the sealing compound to provide mechanical stability to the insulating glass element in the solidified state and to suppress the diffusion of water into the cavity of the insulating glass element which is sealed by the glass panes and the spacer frames.
The insulating glass elements to be sealed can be situated in any arbitrary position during the sealing process. In the case of mechanical methods it is common practice to store the insulating glass elements to be sealed in a substantially vertical way. For explanation purposes, sealing is illustrated by reference to an example of a two-pane insulating glass element with congruent rectangular panes, which glass element is substantially held in a vertical manner. The invention can accordingly be applied to the sealing of multi-pane insulating glass elements, step elements and insulating glass elements made of contoured glass panes, and to the sealing of insulating glass elements which are mounted horizontally or obliquely.
In the case of methods which provide a manual or substantially manual introduction of the sealing material, the insulating glass element to be sealed is always mounted in a horizontal position. Auxiliary units in form of a mounting table are known for supporting the manual method, especially in the case of insulating glass panes of large format, with which the horizontally mounted insulating glass pane can be twisted about a vertical axis in the plane of the glass pane so that user need not run around the pane (see AT 364803 for example). If abutting points occur during the manual sealing which are not situated in a corner region, it is usually proceeded in such a way that after an interruption the filling of the further sealing is commenced at the end of a sealing material bead already placed in the edge joint and is continued in the same direction in which the sealing material was previously introduced. In this process, the insulating glass pane is either not moved at all or twisted at most in the horizontal plane. In the case of manual sealing, the abutting points are typically sealed in such a way that additional or excess sealing compound at the abutting point is simply pressed in or is introduced by a mixing movement of the sealing nozzle in such a way that the material mixes on either side of the abutting point. The sequence of movement of the manual method requires a high level of experience and cannot be automated or only by using very complex machinery. Furthermore, the formation of the abutting points is time-consuming and still frequently leads to air pockets. Even in the case of automatic methods, a sealing nozzle and the insulating glass element to be sealed perform a relative movement with respect to each other for filling the joint edge with sealing compound. The sealing nozzle covers the entire edge of the pane on the circumference of the sealing element and supplies a strand of sealing compound to the edge joint. If the sealing compound bead introduced into the edge joint is supplied without interruption during continuous movement of the sealing nozzle, an abutting point or a connecting point is produced which is formed by the beginning and the end of the sealing compound. Said abutting point can be situated in the region of a corner or a position which is remote from the corners.
The relative movement between the sealing nozzle and the insulating glass elements to be sealed can be produced in the following manner which is generally known:
a) The insulating glass element to be sealed can be fixed during the introduction of the sealing compound, while the sealing nozzle is actively moved around the circumferential edge of the insulating glass element. A respective apparatus is disclosed in WO 2013/056288 A2. The sealing nozzle which supplies the sealing compound can be displaced upwardly and downwardly in the vertical direction in this apparatus via a carriage on a guide beam and is pivotable and rotatable about an axis which is normal to a plane of the glass panes of the insulating glass element. The guide beam is adjustable in a plane parallel to the glass panes in such a way that the sealing nozzle can be moved around the circumferential edge of the insulating glass element held in a substantially vertical position in order to place a sealing compound bead in the straight longitudinal sections of the edge joint and the corner regions and to thus fill the edge joint. In this process, a translatory movement of the sealing nozzle along the longitudinal sections in the region of the corners is combined with pivoting movements.
b) The sealing nozzle is fixed during the sealing process and the circumferential edge of the insulating glass element to be sealed is moved past the sealing nozzle by a respective movement of the horizontally mounted insulating glass element. Such an apparatus is known from U.S. Pat. No. 8,435,367 B2.
c) The movement of the sealing nozzle is combined with the movement of the insulating glass elements to be sealed. The sealing nozzle can be moved along two parallel edge joint sections for example, while the insulating glass element to be sealed remains stationary, and the two edge joint sections which are perpendicularly thereto are filled while the sealing nozzle remains stationary, but the insulating glass element is moved along these directions.
When the sealing compound is introduced into the edge joint in a continuous movement commencing from a position in a corner region, there is only one butt joint of the sealing compound bead. Such a solution with a butt joint in the corner region and continuous introduction of the sealing compound is preferable as far as possible for reasons that will be explained below and is shown in FIG. 1, wherein reference numeral 2 designates the glass panes of the insulating glass element 1, 4 the spacer frame, 5 the remaining edge joint and 6 the sealing nozzle.
In the cases where the introduction of the sealing material into the edge joint must be interrupted for production reasons, e.g., because limited movement ranges of the sealing nozzle and/or the insulating glass element require repositioning because electrical or pneumatic lines or mechanical connections (e.g., shutters that are installed in the interior of the insulating glass element) need to be guided through the sealing compound bead, or because the resupply of the sealing material is interrupted (e.g., because a storage container for the sealing material needs to be changed), and is resumed after interruption, one or several further butt joints are produced along the circumferential edge of the insulating glass element.
Two types of butt joints can fundamentally be distinguished, which are shown in FIG. 6. On the one hand, a butt joint in which the supply of the sealing compound and the relative movement is interrupted at a specific point and the introduction of the sealing compound is recommenced at the spherical end of the material bead previously introduced into the edge joint and continued in the same direction as before, so that the end of the horizontal bead is deformed by the front of the newly introduced material, and an abutting point is formed from two material strands (butt joint of type A). The butt joint of type A can be slightly modified according to the illustration of the variant A′ in the respect that the nozzle is arranged slightly rearwardly offset from the spherical end of the horizontal bead. The newly ejected material enters the material before the end of the horizontal bead and thus virtually “pushes” a small end section of the previously deposited bead in a forward direction with the advancing movement of the nozzle (see FIG. A′, (iii)). For both variants, i.e. for type A and type A′ of the butt joint, the formulation is selected within the scope of the disclosure of the invention that the strand of the sealing compound is attached “in the region of the end” of the material bead previously introduced into the edge joint.
An alternative type of butt joint is formed in that the sealing compound is introduced in a direction towards the end of a material bead situated in the edge joint and both the supply of the sealing material and also the relative movement is interrupted at this point (butt joint of type B). FIG. 6 illustrates in a highly schematic way the formation of the butt joint for these two principal types and the variants of type A/A′.
One problem in all butt joints is generally the possibility of air pockets in the sealing compound and insufficient mixing of the material.
In the case of butt joints of type A, the mutually meeting ends of a sealing compound strand and a sealing compound bead can usually be connected in the edge joint without any such problems, irrespective of where the abutting point is situated on the circumference of an insulating glass element. According to the illustration in FIG. 6 (A), the sealing nozzle can be moved towards the front or front end of an already deposited bead in such a way that the front or end of the bead to be newly deposited can be joined to the front of the bead that was already previously deposited, and the material at the abutting point is deformed by the successive material in such a way that the edge joint is filled with sealing compound completely and without air pockets.
Whereas this problem has substantially been solved by known methods for the case of a butt joint of type B situated in the region of a corner of the insulating glass elements to be sealed, which methods enable the complete connection of the meeting ends of the strand of the sealing compound at the butt joint without any air pockets remaining in the region of the butt joint in the interior of the sealing compound (see the spatula construction for example described in the Austrian patent application A892/2012), no method is known for the case of a butt joint of type B which is not situated in the region of a corner (when the butt joint is therefore situated in an edge joint section between two corners, wherein an edge joint section need not necessarily always be arranged in a straight way in special configurations, but can also have a specific curvature) with which the complete connection of the meeting ends of sealing compound strands without air pockets is possible in this region. According to the illustration in FIG. 6 (B), the fronts or front ends of the beads of sealing compound are spherical, so that the apexes of the beads meet each other when the front of one bead is moved towards the front of an already deposited bead for forming a butt joint of type B. If the sealing nozzle is guided slightly further beyond the meeting point and continues to emit further material, the butt joint will be pressed, but in such a way that air is enclosed between the spacer and the sealing compound.
Interruptions in the introduction of the sealing material and thus the butt joints can especially also be produced in such a way when very large insulating glass elements are to be sealed in an apparatus in which the range of movement of the sealing nozzle is smaller in one direction than the longitudinal dimensions of the insulating glass element, so that the entire length of the edge joint cannot be filled in an interruption-free manner on the respective side of the insulating glass element, at least when the insulating glass element itself stands still. In this case, the insulating glass element to be sealed must be repositioned once or several times after interruption and optional return of the sealing nozzle, i.e., it needs to be further conveyed by a respective measure so that the sealing nozzle can cover the entire length of the edge joint on the side.
The air pockets remaining in the region of the abutting points in the interior of the sealing compound have proven to be disadvantageous in practice because they reduce the mechanical stability of the cured sealing compound and the mechanical stability of the finished insulating glass element. Furthermore, air pockets in the interior of the sealing compound increase water vapor permeability of the sealing compound and thus facilitate the diffusion of water vapor into the intermediate space between the panes. Finally, these air pockets in the interior of the sealing compound are disadvantageous because condensation of water vapor can occur in the cavities formed by the air pockets, which promotes the degradation of the sealing material and can lead to leakages and material breakages.
An apparatus for the automatic filling of the edge joint of two-pane or multiple-pane insulating glass panes with a sealing compound is known from DE 2846785, comprising a pivoting device by means of which the insulating glass pane, during the introduction of the sealing compound as separate strands, is pivoted at least once about 90° over its corner situated in the rear in the transport direction, after a first and second filling nozzle have travelled at first from below to the top along the vertical edge joints situated at the front and the rear in the transport direction when the insulating glass pane is stationary, and a third filling nozzle was moved during the transport of the insulating glass pane along the upper section of the edge joint. After the pivoting, one of the filling nozzles is advanced towards the upper end of the vertical edge joint now situated at the front, or the insulating glass pane is moved to this location, whereupon the remaining edge joint is filled by a movement of the filling nozzle from top to bottom. By applying this apparatus, all butt joints of sealing compound beads are exclusively situated in the corners of the insulating glass pane, so that in this respect no problem is expected with air pockets. However, the pivoting device is difficult to realize with respect to the complexity of the apparatus, or it cannot be used at all or only within limits in the case of larger or very long insulating glass panes.
A method and an apparatus for applying a sealing compound to insulating glass panes is known from DE 69629929 T2, in which a first filling nozzle travels at first along a front joint section from bottom to top on an insulating glass pane which is stationary on a transport device. The first filling nozzle is then moved along the upper joint section and a second filling nozzle along the bottom joint section by means of the transport device under simultaneous transport of the insulating glass pane in order to fill the joint sections. Finally, the first filling nozzle is then moved along the rear joint section from top to bottom again with stationary insulating glass pane in order to fill the remaining joint section. The application of this method and this apparatus also leads to the consequence that all butt joints of sealing compound beads exclusive lie in the corners of the insulating glass pane.
An apparatus for filling an edge joint of an insulating glass pane with a sealing compound is finally known from DE 4009441 A1, which is rotatably mounted on a carriage about an axis which is normal to the insulating glass pane, which carriage is displaceable on its part parallel to the plane of the insulating glass pane along mutually perpendicular guides. This apparatus comprises a scanning finger which is arranged to travel in advance in the direction of movement for detecting the depth of the edge joint.